Interpretive Summary: Oysters have been an important resource in Washington State USA since the mid 1800’s and are intimately associated with recent history of the Willapa Bay estuary just as these shellfish have defined history and culture around much larger US east coast systems. The Willapa Bay oyster reserves were set aside to preserve stocks of the native oyster Ostrea lurida in this estuary, but these stocks were overfished and replaced with the introduced Pacific oyster Crassostrea gigas in the late 1920’s. Pacific oysters have spawned and set naturally in this estuary on a fairly regular basis since that time and formed the basis of a sustainable fishery established on the state oyster reserves. The fishery is managed as an annual sale of oysters to private aquaculture interests. Oysters are harvested mostly by hand from intertidal tracts, usually moved to better growing areas closer to the estuary mouth, and shell is required to be returned to the reserves to perpetuate the fishery. Though harvest for human consumption will remain an important social management goal, oysters have been shown to provide a suite of other ecosystem services. We conducted a survey of the reserves and compared this with historical maps created in the 1890’s. Results suggest that the reserves represent 11.4% of the intertidal habitat in Willapa Bay cover substantial subtidal areas as well. Much of the low intertidal area that was formerly dominated by native oysters is now covered primarily with eelgrass (Zostera marina) which serves as important habitat for many other organisms. Native oysters can still potentially be restored to some of these areas, but the value of both introduced oysters and eelgrass as habitat and ecosystem engineers deserves attention and the Willapa Bay oyster reserves provide an excellent place to study the role of these species.

Technical Abstract:
Oysters have been an important resource in Washington state since the mid 1800’s and are intimately associated with recent history of the Willapa Bay estuary just as they have defined social culture around much larger US east coast systems. The Willapa Bay oyster reserves were set aside to preserve stocks of the native oyster Ostrea lurida in this estuary, but these stocks were overfished and replaced with the introduced Pacific oyster Crassostrea gigas in the late 1920’s. These oysters have spawned and set naturally in this estuary on a fairly regular basis since that time and formed the basis of a sustainable fishery established on the state oyster reserves. The fishery is managed as an annual sale of oysters to private aquaculture interests. Oysters are harvested mostly by hand from intertidal tracts, usually moved to better growing areas closer to the estuary mouth, and shell is required to be returned to the reserves to perpetuate the fishery. Though harvest for human consumption will remain an important social management goal, oysters have been shown to provide a suite of other ecosystem services. A survey of the reserves and comparison with historical maps suggests that they represent 11.4% of the intertidal habitat in this estuary and cover substantial subtidal areas as well. Much of the low intertidal area that was formerly dominated by native oysters is now covered primarily with eelgrass (Zostera marina) which serves as important habitat for many other organisms. Native oysters can still potentially be restored to some of these areas, but the value of both introduced oysters and eelgrass as habitat and ecosystem engineers deserves attention and the reserves provide an excellent place to elucidate the role of these additional conservation targets.